Summary The aim of this study is evaluating iron, ferritin, and transferrin in both serum and CSF in patients of restless legs syndrome (RLS), based on the hypothesis that iron deficiency in the central nervous system (CNS) causes the symptoms as a result of the dysfunction of dopaminergic systems. These parameters, polysomnographic sleep measures, and subjective evaluation of the sleep quality were compared in 10 patients of idiopathic RLS (RLS group) and 10 age‐matched patients of psychophysiological insomnia without RLS symptoms (non‐RLS group). With sleep patterns, sleep latency was longer and sleep efficiency was lower in the RLS group than those in the non‐RLS group. Periodic leg movement index in the RLS group was higher than that of the non‐RLS group. With serum examination, there were no significant differences for the iron, ferritin, and transferrin values between the both groups. With CSF examination, the iron and ferritin values were lower and the transferrin values were higher in the RLS group than those in the non‐RLS group. There was positive correlation between the serum and CSF ferritin levels in the both groups, but the slope of the regression lines for the RLS group was lower than that for the non‐RLS group. These results indicate low brain iron concentration caused by the dysfunction of iron transportation from serum to CNS in patients with idiopathic RLS.

The purpose of the present paper was to evaluate the prevalence of restless legs syndrome (RLS) in a non-institutionalized Japanese elderly population. The subjects consisted of 8900 elderly people >65 years of age belonging to the Seniors Association in Izumo City in November 2000. The present study was conducted in two parts. The phase 1 investigation was a screening by mailed questionnaire and the phase 2 investigation was diagnosis by face-to-face interview. Subjects with possible cases of RLS in phase 1 proceeded to phase 2 and definite cases of RLS were then detected. In phase 1, a total of 3287 subjects completely answering all questionnaire items, were defined as the subjects of the present study. A total of 150 were classified as having 'probable RLS', resulting in a prevalence of 4.6%. These subjects with probable RLS in phase 1 were detected as the subjects of phase 2. By face-to-face interview and various clinical examinations, a total of 35 subjects (nine male, 26 female) were diagnosed as having definite RLS, resulting in a prevalence of 1.06%. Furthermore, seven subjects (two male, five female) with symptomatic RLS were detected and finally 28 subjects (seven male, 21 female) were diagnosed as having idiopathic RLS. It was significantly higher in women for both the total and idiopathic RLS groups (0.60% male vs 1.46% female; 0.46% male vs. 1.18% female, respectively). The prevalence of RLS may be lower in the Japanese elderly than that in Caucasian subjects. These results could enhance understanding of the differences in predisposition between the races.

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The purpose of the present study was to evaluate the relationship between sleep disturbances and depression in the Japanese elderly. Methods: These investigations in the Japanese elderly were carried out with the Geriatric Depression Scale, the Pittsburgh Sleep Quality Index, and questions on restless legs syndrome and nocturnal eating disorder. A total of 2023 people (male: 1008; female: 1015; average age: 74.2 ± 6.3 years) were analyzed by c 2 test and simple and multiple logistic regression. The prevalence of sleep disturbance was 37.3% and that of depression was 31.3%. Female gender and/or older ( ≥ 75 years) age were significantly associated with depression. Characteristics in depressive elderly were poor sleep efficiency, sleep disturbances due to difficulty of initiating sleep (DIS), breathing discomfort, coldness and pain, poor subjective sleep quality and lack of enthusiasm for activities. Sleep disturbances due to using the bathroom, breathing discomfort and coldness and long sleep latency were associated with depression in younger (65-74 years) men. Sleep disturbance due to DIS was associated with depression in older ( ≥ 75 years) men. Sleep disturbance due to pain was associated with depression in younger and older women. Poor sleep efficiency was associated with depression in older women. Poor subjective sleep quality was associated with depression in younger and older men and younger women. Lack of enthusiasm was associated with depression in younger and older men and older women. Restless legs syndrome was statistically significantly associated with depression in younger men. It is concluded that sleep disturbance and depression among the Japanese elderly are closely related symptoms. The features of sleep disturbance with depression differed with sex and age.